NAME

rndc.conf - rndc configuration file

SYNOPSIS

rndc.conf

DESCRIPTION

rndc.conf is the configuration file for rndc, the BIND 9 name server
control utility. This file has a similar structure and syntax to
named.conf. Statements are enclosed in braces and terminated with a
semi-colon. Clauses in the statements are also semi-colon terminated.
The usual comment styles are supported:
C style: /* */
C++ style: // to end of line
Unix style: # to end of line
rndc.conf is much simpler than named.conf. The file uses three
statements: an options statement, a server statement and a key
statement.
The options statement contains five clauses. The default-server clause
is followed by the name or address of a name server. This host will be
used when no name server is given as an argument to rndc. The
default-key clause is followed by the name of a key which is identified
by a key statement. If no keyid is provided on the rndc command line,
and no key clause is found in a matching server statement, this default
key will be used to authenticate the server's commands and responses.
The default-port clause is followed by the port to connect to on the
remote name server. If no port option is provided on the rndc command
line, and no port clause is found in a matching server statement, this
default port will be used to connect. The default-source-address and
default-source-address-v6 clauses which can be used to set the IPv4 and
IPv6 source addresses respectively.
After the server keyword, the server statement includes a string which
is the hostname or address for a name server. The statement has three
possible clauses: key, port and addresses. The key name must match the
name of a key statement in the file. The port number specifies the port
to connect to. If an addresses clause is supplied these addresses will
be used instead of the server name. Each address can take an optional
port. If an source-address or source-address-v6 of supplied then these
will be used to specify the IPv4 and IPv6 source addresses
respectively.
The key statement begins with an identifying string, the name of the
key. The statement has two clauses. algorithm identifies the
encryption algorithm for rndc to use; currently only HMAC-MD5 is
supported. This is followed by a secret clause which contains the
base-64 encoding of the algorithm's encryption key. The base-64 string
is enclosed in double quotes.
There are two common ways to generate the base-64 string for the
secret. The BIND 9 program rndc-confgen can be used to generate a
random key, or the mmencode program, also known as mimencode, can be
used to generate a base-64 string from known input. mmencode does not
ship with BIND 9 but is available on many systems. See the EXAMPLE
section for sample command lines for each.

EXAMPLE

options {
default-server localhost;
default-key samplekey;
};
server localhost {
key samplekey;
};
server testserver {
key testkey;
addresses { localhost port 5353; };
};
key samplekey {
algorithm hmac-md5;
secret "6FMfj43Osz4lyb24OIe2iGEz9lf1llJO+lz";
};
key testkey {
algorithm hmac-md5;
secret "R3HI8P6BKw9ZwXwN3VZKuQ==";
};
In the above example, rndc will by default use the server at localhost
(127.0.0.1) and the key called samplekey. Commands to the localhost
server will use the samplekey key, which must also be defined in the
server's configuration file with the same name and secret. The key
statement indicates that samplekey uses the HMAC-MD5 algorithm and its
secret clause contains the base-64 encoding of the HMAC-MD5 secret
enclosed in double quotes.
If rndc-stestserver is used then rndc will connect to server on
localhost port 5353 using the key testkey.
To generate a random secret with rndc-confgen:
rndc-confgen
A complete rndc.conf file, including the randomly generated key, will
be written to the standard output. Commented-out key and controls
statements for named.conf are also printed.
To generate a base-64 secret with mmencode:
echo"knownplaintextforasecret"|mmencode

NAMESERVERCONFIGURATION

The name server must be configured to accept rndc connections and to
recognize the key specified in the rndc.conf file, using the controls
statement in named.conf. See the sections on the controls statement in
the BIND 9 Administrator Reference Manual for details.